I drove a friend home tonigh and after the truck was up around 190 I started driving it like I would normaly. I would push down the pettle to pull the truck up to 25 mph. I would get some sort of sound that resembles the one I get if I put the pettle to the floor. I just ordered a 4" cat back and will report back on if it is just the exhaust pipe. In the time betwene now and then what are some things I can do to check if the turbo is going bad? My truck is a 01 by the way.